The present invention relates in general to protecting elements and mechanisms from the atmosphere and other invironments and more particularly concerns novel apparatus and techniques for economically and reliably protecting elements such as electronic potentiometers and pressure transducers from the effects of oxidation, humidity, dirt and contaminants with a negligible increase in cost that is relatively inexpensive and easy to fabricate without interfering with the function of the component.
In order to protect certain elements from the adverse effects of the surrounding environment, coverings such as paints or rubberized material may be used. These coverings, although perfectly acceptable in many applications, pose certain difficulties where relative motion must be permitted after the covering is installed. Another method is to fill the cavity wherein this element is located with an inert gas or liquid. To prevent this liquid or inert gas from escaping, a seal is installed to permit access through the liquid or gas. Frequently, seals can be designed to meet the performance desired. For example, to protect a rotary potentiometer, a shaft seal is installed around the rotary shaft. For protecting a pressure measuring transducer, an isolation diaphragm is used to seal a certain amount of an inert liquid, such as silicone, between the transducer and one side of the isolation diaphragm. In this method, an external pressure can be measured by the transducer after the pressure has been communicated through the liquid.
It is an important object of the invention to provide improved apparatus and techniques for protecting elements from contamination.
It is an object of the invention to protect a pressure deformable diaphragm without interfering with its operational characteristics such as spring rate, hysteresis and other parameters.
It is a further object of the invention to achieve the preceding objects while allowing relative movement between at least one protected element and another element.
It is still another object of the invention to achieve one or more of the preceding objects while protecting electrical elements, such as potentiometers, strain gauges and pressure transducers.
It is still a further object of the invention to achieve one or more of the preceding objects with apparatus that is relatively inexpensive, reliable and relatively easy to install.